117 replies to this topic

[Guitarman]

Here is a repost from another thread by Mimo. Great work!!!

I stumbled across this method of getting rid of yellowing in it's infancy on the English Amiga Forumsand what can I say other than it really works.
As an example here are before and after shots of my very yellow 800XL.
This looked like it had been near a window as the yellowing was much worse on the right hand side. After a day and a half soaking the results speak for themselves.





I have also tried this on a 400 and that worked very well. I tried some keys off a XEGS, but results were not so good-I plan to try this again when I have some spare time.
I also plan on doing a 400,800,65XE and various other bits and bobs- stay tuned.

I take no credit for this, I am just following other peoples instructions

IF YOU DO THIS-IT IS ENTIRELY AT YOUR OWN RISK

Here is a brief resume of the how/why

Quote

1. We have learned that a magic concoction has been created that can reverse the years of yellowing of plastics, caused by the brominated flame retardants (which were added to the plastic when it was a masterbatch) migrating to the surface of the plastic and attracting oxygen molecules which become attached by a co-ordinate bond.

2. Bromine molecules are susceptible to ultra-violet light, in that chemical bonds involving bromine molecules can become destabilised if irradiated by UV light. This is what we are exploiting to remove the oxygen molecule from the brominated flame retardant.

3. The yellowing can be reversed to a degree by immersing parts in hydrogen peroxide or "Oxy" on their own, however, on their own they don't do that much; what is needed is a chemical called TAED (tetra acetyl ethylene diamine), which is a chemical found in the "Oxy" type laundry boosters. Why is this useful? It's useful because it catalyses perborates and percarbonates in the "Oxy" to produce peroxides; it can also catalyse hydrogen peroxide, which is exactly what we want. This is what makes the mixture much more potent.

4. The optimum mixture and conditions for reversing yellowing of plastics seems to be the following:-

A) Hydrogen peroxide solution, the strongest you can lay hands on;
B) UV light, either as sunlight or a UV lamp;
C) Approx 1/4 teaspoonful per gallon of "Oxy" laundry booster.

Parts immersed in this mixture will have the yellowing reversed in six to eight hours on average. Severe yellowing may take longer but it will only be a matter of a day or two. The mixture once made will last about four days before all of the peroxide is spent.

5. A more recent development is that the mixture can be made into a gel. Initial tests with Xanthan Gum added to the original mixture have shown that it can be made into a thicker material which can be brushed onto surfaces. This mixture foams up but still removes the yellowing when put under UV light, and can remove yellowing in four to six hours. This method also drastically cuts down on the amount of liquid required and means large areas can be treated at a relatively low cost. Other thickeners such as corn starch, hydroxy ethyl cellulose, wallpaper paste, latex or similar inert thickener may also work, however, tests are in the early stages, feel free to try some of these and report back if they work.

6. Recent tests by Lorne have shown that powdered hair bleach and hydrogen peroxide solution can give a similar effect to the original "Oxy" mixture, however, there may be side effects associated with using this material; early tests have seen adverse effects on paint and stickers may also be affected by this product. The original "Oxy" mixture does not affect paint or stickers, unless the stickers are held on with a water based glue or are paper stickers.

7. If you are planning to do this in a hot climate, please be aware that this mixture will heat up during the day. Lorne is in Arizona and found that temperatures in excess of 100F (38C) and beyond were encountered, which caused some warping and distortion of large pieces. If this is the case where you live, always add the component to a cold mixture and check the temperature during the day.

We will add to this original post in the thread as we learn more. If you wish to read the original thread, it's here:-

http://www.vintage-c....ad.php?t=11877

The story continues.........

[Merlin]

OK, guess who has come over to the "dark side" to help you guys out with this....?

Mimo has started a separate thread just covering this subject, so that I can support you and explain how it works.

Science abuse rules!!!

[Ogma]

I picked up a computer from a moving sale today and the keyboard was filthy and spattered with ancient, dried "gunk"...

To remove it, I tried oven cleaner (ala Easy-Off) on the casing (not the keys... yet) and I was stunned at how well (and fast) it worked! Has anyone else tried this???


~Scott

[flashjazzcat]

Just received a brand new keyboard from Best Electronic today:







Case is just slightly tarnished, but shouldn't take much work, hopefully.

[flashjazzcat]

After dousing the case in a warm bath with a dash of thick bleach and a scoop of Oxy Laundry Powder, I lightly cleaned it with a very mild abrasive cleaner (containing bleach), gave it a scrub with a dishwashing brush and some spray bleach, then left it to soak for half an hour. I'm extremely pleased with the result:



In actuality the case wasn't too badly tarnished: it must have been mainly surface discolouration. I'm only sorry I don't have a better "before" pic (see post above).

[spookt]

flashjazzcat, on Thu Feb 12, 2009 1:04 PM, said:

After dousing the case in a warm bath with a dash of thick bleach and a scoop of Oxy Laundry Powder, I lightly cleaned it with a very mild abrasive cleaner (containing bleach), gave it a scrub with a dishwashing brush and some spray bleach, then left it to soak for half an hour. I'm extremely pleased with the result:

Restored.jpg

In actuality the case wasn't too badly tarnished: it must have been mainly surface discolouration. I'm only sorry I don't have a better "before" pic (see post above).

Minty fresh Looks nice, a lot nicer than some of my XEs.

[wood_jl]

Bleche Wite tire cleaner (caustic stuff) is great for getting greasy dirt out of textured plastic - with a toothbrush.
Try to keep it off the metal parts; it's harsh and I've had it etch stains in aluminum when I was using it to clean car engines (hoses, etc).

For scratched 800XL cartridge doors, I used 400-grit sandpaper wet, as if it were a car fender. After that, chrome polish (sorta gritty) and then car polish (fine) and of course working "with the grain" and now they look great!

[kamakazi]

I've been using a product called "LA's Totally Awesome". It doesn't contain any bleach, ammonia or other harsh chemicals. While it usually doesn't bring back the "new" look...it is great for removing unGODly build-up of smoke, dust and other environment enemies. This stuff has actually turned my cigarette-tainted walls back to white! You could see the tar just roll off.

[ClausB]

Just finished cleaning my nephew's old 800. Dishwasher worked well. I even put all the keys in the silverware basket and tied a rag over the top so they wouldn't fly out. Now they're shiney again.

When I put it back together, I found some of the keys are intermittent. Looked at the back of the keyboard with a magnifier and saw many broken solder joints - little dark circles around the pins. I'll have to resolder them.

Anyone seen that before? Wondering if it's common or if this unit was temperature stressed or pounded too hard or something.

Edited by ClausB, Sat Apr 18, 2009 4:03 PM.

[wood_jl]

REPLACING MISSING XL METAL TRIM???

So my latest 800XL acquisition has been disassembled, cleaned, and reassembled.

My standard procedure? Clean everything (in the bathtub) with Bleche Wite Tire Cleaner and a toothbrush. Use gloves - this stuff is bad to get on the hands. It is also very bad to breathe fumes, so use it carefully. If you spray a big mist, the fumes will make your eyes water and nose burn. Can't stand a nasty keyboad, so remove keycaps, brush with toothbrush and tire cleaner, and drop each one into a sink of hot water so you don't have to rinse each one. Be sure to use a plastic bag over your hand or glove.

The white, textured surface of the 800XL really looks nasty when you get an Ebay computer. This stuff - and the toothbrush - really do it some justice.

The last 800XL was Taiwian, and the brown part (surrounding the keyboard) was fastened on with screws.

This one is Hong Kong. The brown part does NOT come off. It is a separate casting, but it's been sorta "welded" in place in a few spots, with something hot - in the factory. As a result, you CAN NOT disassemble that part, and you can NOT take off the clear plastic strip (which covers the power light and function button labels). When you're done washing, there is - of course - water and moisture trapped all in there, as well as moisture trapped between the white and brown plastic layers, which you can't disassemble. I've had a POWERFUL fan blowing on it for most of a day, and I'm going to leave it for a long time, as you don't want moisture trapped in there and then introduced to your computer after reasssembly. One thing for sure, the models that disassemble (can take off the brown part with tiny screws) are definitely preferable when it comes to cleaning!!!

The Hong Kong model has "Chelco" cast in all the plastic parts. The motherboard also says it. They must have been a big XL-era contractor. I also have an SIO cable that says "Chelco" on the plugs.

This computer is MISSING the aluminum trim that is below the function keys, and just to the left of the power light. It really sucks, because this thing is cleaning up like new!! No yellowing, and I've restored the cartridge doors with sandpaper and polish.

I need to put something there, so I am going to try (please don't laugh) a piece of pop can. I'm going to cut paper to the right size, then trace it on a pop can (obviously inside out so uncolored size is out). Then, I'm going to take sandpaper and attempt to make a "grain" to match the function keys, then polish a little. Then, stick on with contact cement.

I can't think of anything else to do. This computer now looks so beautiful and clean that the missing trim is now the only problem and appears to be MORE of a problem than when it was all dirty!!! SOMEONE COME UP WITH A BETTER IDEA!!!

Edited by wood_jl, Sun Apr 19, 2009 10:17 AM.

[flashjazzcat]

Hope it works! I'd love to see some photos.

Edited by flashjazzcat, Sun Apr 19, 2009 10:57 AM.

[wood_jl]

flashjazzcat, on Sun Apr 19, 2009 9:57 AM, said:

Hope it works! I'd love to see some photos.

Well, the pop can trim worked, but it took a couple of tries! The pop can metal is SO thin, I easily distorted it and stretched the metal the first time.

I cut open several pop cans, and found they sora had a "grain" to them already. I oriented the cutout so it would look similar to the function keys. The metal is too thin to sand (or do anything with) so you just have to stick it on.

I made a pattern with a piece of 3x5 notecard, then traced it onto the pop can metal with a sharpie, then cut on the inside of the mark.

First mistake was to try to straighted out the new trim piece, because it was curled like the roundness of the pop can. That stretched it and warped it, and it looked like crap.

Contact cement is what is needed, but it has to be thin. The contact cement I used was a little too thick and looked clumpy. For the second try, I diluted it a little with Coleman camp stove fuel ("white gas") and carefully put it on both parts. If there's any clumps, the thin pop can metal will warp when you press it down and it looks like junk.

After it dries, line it up carefully at the top, and only then "uncurl" the new trim piece as you apply it, but it's so thin it's easy to ruin it. Then, I applied a little more contact cement to the very bottom (where the sharp bend is) and let it dry. Finally, make the little edge bend with your thumb, but it's easy to ruin it at this point.

It looks good! I took a pic, but the flash lighting makes it looks much worse than it does in normal lighting. It's a pretty good match.

Unfortunately, the function keys remain a little scratched. I tried some chrome polish on one, but it didn't seem to do anything, and I was afraid to cut into the finish very much so I decided to leave well enough alone. The standard Bleche Wite tire cleaner and toothbrush treatment got the case looking nice, and removing/straightening/wet sanding/polishing on the old cartridge doors got them looking bright and new again!

[flashjazzcat]

Thanks for the pic. It looks beautiful: an excellent job!

[mimo]

wood_jl, on Wed Apr 22, 2009 3:51 PM, said:

flashjazzcat, on Sun Apr 19, 2009 9:57 AM, said:

Hope it works! I'd love to see some photos.

Well, the pop can trim worked, but it took a couple of tries! The pop can metal is SO thin, I easily distorted it and stretched the metal the first time.

I cut open several pop cans, and found they sora had a "grain" to them already. I oriented the cutout so it would look similar to the function keys. The metal is too thin to sand (or do anything with) so you just have to stick it on.

I made a pattern with a piece of 3x5 notecard, then traced it onto the pop can metal with a sharpie, then cut on the inside of the mark.

First mistake was to try to straighted out the new trim piece, because it was curled like the roundness of the pop can. That stretched it and warped it, and it looked like crap.

Contact cement is what is needed, but it has to be thin. The contact cement I used was a little too thick and looked clumpy. For the second try, I diluted it a little with Coleman camp stove fuel ("white gas") and carefully put it on both parts. If there's any clumps, the thin pop can metal will warp when you press it down and it looks like junk.

After it dries, line it up carefully at the top, and only then "uncurl" the new trim piece as you apply it, but it's so thin it's easy to ruin it. Then, I applied a little more contact cement to the very bottom (where the sharp bend is) and let it dry. Finally, make the little edge bend with your thumb, but it's easy to ruin it at this point.

It looks good! I took a pic, but the flash lighting makes it looks much worse than it does in normal lighting. It's a pretty good match.

Unfortunately, the function keys remain a little scratched. I tried some chrome polish on one, but it didn't seem to do anything, and I was afraid to cut into the finish very much so I decided to leave well enough alone. The standard Bleche Wite tire cleaner and toothbrush treatment got the case looking nice, and removing/straightening/wet sanding/polishing on the old cartridge doors got them looking bright and new again!

looking good. FYI you can use wet and dry paper to polish up the "function buttons" and I probably have the metal piece you are missing, If I can (a) get it off in one piece (b) not be too scared of the postage I can send it to you (PM me!)

[bf2k+]

wood_jl, on Sun Apr 19, 2009 12:15 PM, said:

...
I need to put something there, so I am going to try (please don't laugh) a piece of pop can. I'm going to cut paper to the right size, then trace it on a pop can (obviously inside out so uncolored size is out). Then, I'm going to take sandpaper and attempt to make a "grain" to match the function keys, then polish a little. Then, stick on with contact cement.

I can't think of anything else to do. This computer now looks so beautiful and clean that the missing trim is now the only problem and appears to be MORE of a problem than when it was all dirty!!! SOMEONE COME UP WITH A BETTER IDEA!!!

Used the color side of a Budweiser can

[Tezz]

wood_jl, on Wed Apr 22, 2009 3:51 PM, said:

Unfortunately, the function keys remain a little scratched. I tried some chrome polish on one, but it didn't seem to do anything, and I was afraid to cut into the finish very much so I decided to leave well enough alone.

if you change your mind and decide to sacrifice the original surface finish on the console keys to remove those scratches, I've used the polishing tool on a dremel with a metal polish paste which brings the keys up to a shiney chrome finish. Remember to clamp the keys down and wear eye protection if you do it, the dremel tools can be pretty powerful and send the keys flying!

I personally decided to go this way when I was restoring the xl's because the surface of the console keys seems to quickly wear down with use over time to expose the chrome so has that unsightly patch in the middle of the key. With the surface polished away the chrome effect was even across all the keys and looked better although I must admit I do prefer the look of the brushed metal that they added to the surface. It's a shame it doesn't wear too well.

[spookt]

Tezz, on Wed May 6, 2009 8:25 PM, said:

wood_jl, on Wed Apr 22, 2009 3:51 PM, said:

Unfortunately, the function keys remain a little scratched. I tried some chrome polish on one, but it didn't seem to do anything, and I was afraid to cut into the finish very much so I decided to leave well enough alone.

if you change your mind and decide to sacrifice the original surface finish on the console keys to remove those scratches, I've used the polishing tool on a dremel with a metal polish paste which brings the keys up to a shiney chrome finish. Remember to clamp the keys down and wear eye protection if you do it, the dremel tools can be pretty powerful and send the keys flying!

I personally decided to go this way when I was restoring the xl's because the surface of the console keys seems to quickly wear down with use over time to expose the chrome so has that unsightly patch in the middle of the key. With the surface polished away the chrome effect was even across all the keys and looked better although I must admit I do prefer the look of the brushed metal that they added to the surface. It's a shame it doesn't wear too well.

Any chance of a piccy ?

[mimo]

spookt, on Wed May 6, 2009 10:01 PM, said:

Tezz, on Wed May 6, 2009 8:25 PM, said:

wood_jl, on Wed Apr 22, 2009 3:51 PM, said:

Unfortunately, the function keys remain a little scratched. I tried some chrome polish on one, but it didn't seem to do anything, and I was afraid to cut into the finish very much so I decided to leave well enough alone.

if you change your mind and decide to sacrifice the original surface finish on the console keys to remove those scratches, I've used the polishing tool on a dremel with a metal polish paste which brings the keys up to a shiney chrome finish. Remember to clamp the keys down and wear eye protection if you do it, the dremel tools can be pretty powerful and send the keys flying!

I personally decided to go this way when I was restoring the xl's because the surface of the console keys seems to quickly wear down with use over time to expose the chrome so has that unsightly patch in the middle of the key. With the surface polished away the chrome effect was even across all the keys and looked better although I must admit I do prefer the look of the brushed metal that they added to the surface. It's a shame it doesn't wear too well.

Any chance of a piccy ?

I just took the silver keys off and used "wet and dry" Looks like new!, I would post pictures but can't remember which XL I did as like I said, it looks like new

[Tezz]

spookt, on Wed May 6, 2009 10:01 PM, said:

Any chance of a piccy ?

Sure no prob!
I've taken one quickly with my phone just now, it's not great but you can just about see the effect on the keys

Attached Thumbnails

• 

[Tezz]

mimo, on Thu May 7, 2009 11:41 AM, said:

I just took the silver keys off and used "wet and dry" Looks like new!, I would post pictures but can't remember which XL I did as like I said, it looks like new

Cool, I'd like to see how that came out. I used 1200 grade wet n dry too but just on the small trim parts of the xl and glued them back down in place. I don't think they are clear enough to see well in the photo above. I've done two xl's that way. none of them have had the oxy gel treatment yet only a good clean so they are still a bit discoloured.

[wood_jl]

More pics, please!!! (love this stuff!)

Maybe a higher-rez one with your real camera. But boy, that looks good!!!

Tezz, on Thu May 7, 2009 9:40 AM, said:

spookt, on Wed May 6, 2009 10:01 PM, said:

Any chance of a piccy ?

Sure no prob!
I've taken one quickly with my phone just now, it's not great but you can just about see the effect on the keys

[spookt]

Tezz, on Thu May 7, 2009 4:40 PM, said:

spookt, on Wed May 6, 2009 10:01 PM, said:

Any chance of a piccy ?

Sure no prob!
I've taken one quickly with my phone just now, it's not great but you can just about see the effect on the keys

Looks nice. Thanks for the pic

[mimo]

Actually thinking back I just used "dry" as the finish was too smooth and shiny with "wet"

[wood_jl]

I just got a NICE (!!!!!) 400 from Ebay. Not brand new, but as-new, and in the box!!! I am thrilled, as I have not touched one of these for perhaps 25 years, and one was my first (!!!) computer!!

I do not anticipate actually using it much; I just like to hold it like a baby!

One problem, however, is the RF sheilding on the inside of the cartridge door. It appears to have been previously affixed to the cartridge door with some black 2-sided foam tape (or something like that) which has deteriorated and pseudo-liquified and the piece of shielding has released. I got black gook all over my hands when I touched it. Then I closed the catridge door and got that gook all over the nameplate!!!!!! It was a terrible mess, made in an instant.

I was able to (barely) remove the mess with solvent - Coleman fuel.

I guess I will use the fuel to remove the gook, and then I am thinking I will reattach the piece of shielding with clear silicone.

Any thoughts or suggestions on this? I think I have seen the Atari 800 suffer from the same, in online (Ebay) pictures. I am thinking this may be common, but I'd like to hear from those who actually know. How did YOU fix this? Thanks!

PS - I am assuming adding 48K and monitor port are impractical, hence this is just a pleasant curiosity.

[mimo]

I have read, (but not tried) that 5200 s-video mods from 8bitdomain will work on a 400, you can also make your own, search for "little brother grows up", but be sure to search for the addendum as the original instructions had some errors.I intend to try this one day, but to be honest the 400 has pretty good RF output, much better than the XL or 7800
As for 48k upgrade, I think that myatari.com has some for sale, or again you can make your own with a few parts and a donor 16k RAM board.You also have to add 3 or 4 wires to the motherboard.

I love the 400 as well, It was my second computer (after a ZX81) thats why I have 3 of them (all 3 have the metal shield on the cart door fallen off, so yes it is a common problem, never got around to fixing them though)

Edited by mimo, Fri May 15, 2009 7:21 AM.